Woven article as a carpet scrim

ABSTRACT

A BACKING OR SCRIM WOVEN FROM YARNS OF SYNTHETIC PLASTIC, USEFUL IN PARTICULAR FOR NEEDLE PUNCH CARPET PRODUCTS AND THE LIKE IS DISCLOSED. THE INVENTION IS CHARACTERIZED BY THE YARNS IN THE WARP OF THE SCRIM BEING &#34;CROWDED&#34; AND DIMENSIONALLY SELECTED TO HAVE A WIDTH TO THICKNESS RELATIONSHIP TO INSURE MINIMUM FOLDOVER, THEREBY RESULTING IN A LOOSE WARP, DESPITE CROWDING AND POSSESSING A HIGH DEGREE OF &#34;SPRINGINESS&#34; TO INHIBIT WIDTH REDUCTION DUE TO MECHANICAL WORKING WHEN WOVEN AND USED IN THE CARPET PRODUCT. A FURTHER CHARACTERISTIC IS THE USE OF A HEAT SOAKED FILL YARN, WHEREIN THE HEAT SOAKING IS ACCOMPLISHED PRIOR TO WEAVING, TO REDUCE SHRINKING IN THE FILL DIRECTION.   THE FINAL SCRIM FABRIC IS REMARKABLY NON-SHRINKABLE, EVEN WHEN SUBJECTED TO HOT LATEXING AND DYEING PROCEDURES IN CARPET MANUFACTURE.

Oct. 3, 1972 w. J. HOGG ETAL 3,695,983

WOVEN ARTICLE AS A CARPET SCRIM Filed. Aug. 10, 1970 4 Sheets-Sheet 1INVENTORS WILL/AM J. H066 SEPT/MUS A. HARV/N CHARLES .4. JL4CK$0N JOSEPHC WH/TESEL Oct. 3, 1972 w HOGG ET AL 3,695,983

WOVEN ARTICLE AS A CARPET SCRIM INVENTORS' WILL/AM .1 H066 SEPT/MUS A.HARw/v,

CHARL E5 A. JACKSON JOSEPH a. WH/TESEL Oct. 3, 1972 w J HOGG ETAL3,695,983

WOVEN ARTICLE AS A CARPET SCRIM Filed Aug. 10, 1970 4 Sheets-Sheet :5

INVENTORS WILLIAM J. H066 SEPT/MUS A. HARV/N CHARLES A. JACKSON JOSEPHC. WH/TESEL Oct. 3, 1972 w J HOGG ET AL 3,695,983

WOVEN ARTICLE AS A CARPET SCRIM Filed Aug. 10, 1970 4 Sheets-Sheet 4 I.I. I. 5972 Fig.6

INVENTORS WILL/AM J. H066 SEPT/MUS A. HARVl/V;

CHARLES A. JACKSON JOSEPH C. WH/TESEL m? mmwwwm Unease-es Patent one3,695,983 Patented Oct. 3, 1972 3,695,983 WOVEN ARTICLE AS A CARPETSCRIM William J. Hogg, Dalton, and Charles A. Jackson,

Sterling, N.J., and Septimus A. Harvin and Joseph C.

Whitesel, Waynesboro, Va., amignors to Thiokol Chemical Corporation,Bristol, Pa.

Filed Aug. 10, 1970, Ser. No. 69,508 Int. Cl. D03d 11/00, 13/00; B32b/00 U.S. Cl. 161-71 15 Claims ABSTRACT OF THE DISCLOSURE A backing orscrim woven from yarns of synthetic plastic, useful in particular forneedle punch carpet products and the like is disclosed. The invention ischaracterized by the yarns in the warp of the scrim being crowded anddimensionally selected to have a. width to thickness relationship toinsure minimum foldover, thereby resulting in a loose warp, despitecrowding and possessing a high degree of springiness to inhibit widthreduction due to mechanical working when woven and used in the carpetproduct. A further characteristic is the use of a heat soaked fill yarn,wherein the heat soaking is accomplished prior to weaving, to reduceshrinking in the fill direction.

The final scrim fabric is remarkably non-shrinkable, even when subjectedto hot latexing and dyeing procedures in carpet manufacture.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to a new and improved textile fabric. More particularly itrelates to a novel woven scrim for textile fabrics such as carpets andthe like, formed by the needling, or needle punching process. It alsorelates to a process for making the scrim, and to a carpet fabric madetherefrom. In its carpet fabric aspect the invention is made from aloose batt, or web of semiparallel fibers as obtained from a garnet ortextile carding machine. The fibers in the batt can be natural, e.g.,wool, cotton or synthetic staple such as is used for outdoorindoorcarpeting. The batt of fibers is layed onto, or over the novel plasticscrim, and the loaded scrim is then fed into a needling, or needlepunching machine. The needles, usually numbering in the thousands, punchthe batt into and through the scrim so that a mass of face fibers coversthe top, and to a lesser degree the underside thereof. The punched scrimmay be turned over and the process above described repeated; however,punching from one side only is also feasible and some carpets are somade. The underside of the fabric is then usually given a coat of latexwhich serves to hold the fibers in the fabric body. An additional bottomlayer of foam rubber or other backing material may be attachedadhesively to complete the carpet fabric.

DESCRIPTION OF THE PRIOR ART The above referred to invention alsoincludes within its scope a significantly improved scrim useful in theparticular textile fabric above mentioned. Needle punching in the art oftextile manufacturing has been known for many years in felt making andin conjunction with fibers having felt characteristis. For example,Simpson, H. B. et al. in their U.S. Pat. No. 3,484,283 disclose aplastic felt comprised of staple formed into a batt. The batt is thenlayed over a scrim and fed to needling machines and needle punched inthe conventional manner. The fabric made by the method of Simpson et al.is preferably used in outdoor-indoor carpeting, hence polyolefinmaterials are recommended to be used. J. Zocher, in U.S. Pat.

3,473,205 also discloses a needle punched fabric together with anapparatus for needle punching felt or fiber material into the fabric.Zocher feeds a web of tangled fiber material which is either prepunchedto give it solidity, or has been compacted to render it capable of easytransport to the needle machine. The needle machine is modified by meansof additional barbs on the needles which pick up additional staplefibers which are stored on a fixed part of the machine and punches theminto the web above described. Tesch, G. H., in U.S. Pat. 3,448,502discloses a needle punched fabric with a plastic sheet scrim whichcontains slits to improve its needle punching characteristics. Teschutilizes What he calls a polypropylene foil as scrim, the foil being anoriented plastic film containing diagonal slits, and which is exposed tohot air and/or infrared radiation. The Width of the foil is therebyreduced by about 30%, and its Weight per unit area being reduced toapproximately 50 grams per square meter from an original weight per unitarea of 350 grams per sq. meter. The slits in the polypropylene scrimare alleged to improve its resistance to splittering during needlepunching. Charlton, Jr., R. H., et al., in U.S. Pat. 3,476,626 disclosea needle punched plastic panel having textile simulatingcharacteristics. Charlton et al. provide a rigid (40 mils or more inthickness), but flexible, scrim upon which is layed a fiber web, or battwhich is needle punched into the sheet. Provision is also made forheating the scrim for softening thereof prior to needling.

Other needle punched fabrics are known to the art, as are fabrics havingpolyolefin scrims. In fact such scrims have been in use for the pastseveral years. In particular, a woven scrim of polyolefin yarns made ona conventional shuttle loom, the yarns being extruded ribbons, has alsorecently come into more or less general use. In fact a scrim Woven on aconventional shuttle loom using polyolefin ribbon yarns in a weaveconfiguration of twelve ends per inch in the warp and eight ends perinch in the weft, or fill (12 x 8 configuration), has performedsatisfactorily for the last few years when used in needle punchedfabrics.

However, with the recent arrival of the much more economicalshuttle-less, high speed looms, such as the so-called Sulzer looms"manufactured and sold throughout the World by Sulzer Brothers Ltd., ofWinterthur, Switzerland, and which are capable of weaving the above 12 x8 scrim fabric, serious problems were unexpectedly encountered when a 12x 8 scrim was woven by means of this machine. In contrast, woven primarybacking of these same materials for tufted carpets did not present anysignificant problems When changing from shuttle to shuttle-less weavingmachines. Other problems were encountered some of which may or may notbe related to the change in operation from the old to the new machinesfor Weaving scrims for needle punched fabrics. Problems which appeardefinitely related to the new machines include; carpet faceunsightliness caused by scrim yarn exposure in the carpet face; shiftingof the fiber batt after deposit on the scrim fabric before needling; andfilling yarns at the selvages of the scrim fabric being punched orpulled through to the carpet face by the needles. An important aspect ofthis invention is the overcoming of excessive scrim, and thereforecarpet width reduction which appeared to be the result of both themechanical action of needling and subsequent length, or warp-wisetensions applied thereto in processing, and of heating effectsassociated with latex application and curing.

SUMMARY OF THE INVENTION An important object of the invention,therefore, is to provide a woven article for a needle punched fabricwherein the arrangement and type of warp and fill yarns is such as toresult in a scrim of high commercial quality and improvedserviceability.

Another object of this invention is to provide a scrim for a needlepunched fabric which though woven on a shuttle-less loom performscommercially satisfactorily.

An additional object of this invention is to provide a needle punchedfabric useful as a carpet wherein the scrim therefor is a woven articleof thermoplastic material having a crowded warp of ribbon like yarns anda relatively open fill of ribbon-like yarns.

Still another object of this invention is to provide an article of thecharacter described wherein at least the fill yarns are treated prior toWeaving to prevent shrink of the article when used for a scrim in aneedle punched fabric.

Yet still another object of this invention is to provide a scrim of thetype referred to wherein tentering thereof is eliminated.

A yet additional object of this invention is to provide a woven scrim ofthe character described wherein the selvage thereof is reinforced andsufiiciently secured to substantially eliminate fill yarn push throughto carpet face.

Another object of this invention is to provide a fabric of the characterreferred to wherein the yarns, warp and fill, are treated with a mineraloil or other non-reacting (to the material of the yarns) substance toimprove the fabrics needle punching characteristics.

A still additional object of this invention is to provide a fabric scrimof the character described which possesses high strength retentioncharacteristics after needle punchmg.

Another yet important object of this invention is to provide a processfor making a scrim of the character described for use in needle punchedfabrics.

Described briefly the article and method of the invention comprises ascrim for a needle punched fabric, the combination of a needle punchedfabric together with the scrim, and a process for making the scrim. Thescrim of the invention is a woven article, preferably of thermoplasticmaterial such as polyolefin, wherein the number of warp yarn ends perunit length exceeds the number of fill yarn ends, or picks per unitlength in a ratio of about 3 to 1, or higher. In addition to the novelwarp-to-fill ends per unit length relationship, the invention furthercontemplates that at least the fill yarns be subject to an additionalheat soaking or annealing step prior to weaving, thereby producing ascrim of substantially zero shrink capability.

In describing the present invention certain terms and expressions willbe used frequently throughout the specification and claims. It isbelieved, therefore, that the invention will be better understood in thelight of the following definitions which are set forth below in asincere 4 attempt to promote this understanding and also to give clearevidence of the fact that this invention represents a genuine advance inthe needle punching textile .arts.

COVER FACTOR To artisans in the textile arts Cover Factor is a term usedto indicate the degree of openness in the Warp, in the fill, or in bothof a fabric. It is a dimensionless number obtained as the product of thenumber of yarn ends per inch (warp or fill) and the yarn width ininches. Thus a fabric having 10 ends per inch in the warp and having ayarn Width of 0.10 inch is said to have a Warp Cover Factor of 1.0.However, it should be noted that heretofore in the art, Cover Factorsgreater than one are relatively meaningless, since the term is mostlyused by artisans concerned with round yarn fabrics, hence a Cover Factorabove 1.0 is understood to be a layered fabric rather than an open orclosed fabric. Therefore to better distinguish the fabrics embraced bythe herein described invention a new term, below defined, will beintroduced and used herein.

CROWDEDNESS For the purposes of this invention Crowdedness" isconsidered a rather apt term selected to assist in describing andunderstanding an important characteristic of the inventive fabric withrespect to the warp and/or fill direction. It is of course related toCover Factor; however, for purposes herein, it is a more convenient termbecause, as will become evident, it is more descriptive of the articleinvented. Also, it too is a dimensionless number, being the product ofyarn ends per inch and yarn width, and encompasses openness as Well asclosedness or opaqueness. In the example given above, i.e., a warphaving 10 yarn ends per inch to include multiple strand yarns as onehaving one end per inch, and each yarn 0.10 in. in width would have aCrowdedness No. of 1.0. Clearly then, as stated above, CrowdednessNumber is the product of the number of yarn ends per inch and the widthof the yarn in inches. Obviously for yarns of oval, eliptical, roundetc. cross-sections, the dimensions utilized in the calculation ofCrowdedness N0. is the axis parallel to the plane of the fabric or thediameter, respectively.

A Crowdedness N0. of less than 1.0 indicates an open warp or fill. Forexample, a fabric scrim which has a fill of 6 ends (picks) per inch ofribbon monofilaments 0.100 inches (100 mils) in width has a fillCrowdedness No. of 0.60, must be open (in the fill) in the sense thatthe yarns are spaced apart. Conversely, one having a warp of 30 ends perinch and a ribbon width of 0.050 inch mils) has a warp Crowdedness N0.of 1.50 and must be closed, or for purposes herein must be a crowdedwarp. The following table sets forth in more detail the foregoingconcepts.

Crowdedness Numbers (cover factor) Sample Warp yarns Fill yarnsTheoretical experimental Number Number Scrim Ends Yarn thick- Ends Yarnthick- Warp Fill Warp Fill description, per width, ness, per width,ness, direcdireedirecdirecwarp x fill inch inch inch inch inch inch tiontion tion tion scrim Number:

1 12 x 8 12 0.100 0.002 8 0. 100 0.002 1.20 24 x 6 24 050 002 6 100002 1. 20 24 x 8 24 0. 050 002 8 100 002 1. 20 24 x 11 24 050 002 11 100002 1. 20 28 x 6 28 041 .002 6 109 .002 1. 15 2B. 7 x 6 28. 7 045 002 6109 002 1. 29 28. 3 x 7 28. 3 .045 .002 7 108 002 1. 27 29 x 6 29 .048.002 6 100 .002 1.39 29. 2 x 0 29. 2 048 002 0 100 002 1. 26 30 X 6 30.048 .002 6 100 .002 1. 44 45 x 9 45 040 .0016 9 090 0019 1.

It should be understood that the above tabulated Crowdedness Nos. aremaximum values and are applicable to ribbon yarn which experiencesminimal or zero folding, bunching or other coverage reducing effectsduring weaving. Truly such a perfect scrim is practically, or nearly so,impossible to make; however, as will be seen from what follows,Crowdedness Numbers significantly greater than 1.0 are intended as beingwithin the scope of the invention herein presented.

TENTERING A process wherein a scrim fabric, especially a syntheticplastic fabric, is restrained width-wise, as well as lengthwise whilebeing conveyed over or through a heat zone is known as tentering. Thepurpose of tentering is to preshrink the Woven fabric so that upon beingsubjected to heat later in the carpet manufacturing process furthershrinking will not occur. Tentering usually involves the provision of arelatively large, and often expensive facility. For example, commercialscrim fabrics for carpets usually are supplied in widths of twelveto'fifteen feet hence, a tentering apparatus, if provided, necessarilymust be large enough to handle these scrims.

ANNEALING In the textile arts, especially with regard to synthetics usedtherein, annealing is a process wherein the yarns are heated forspecific times under controlled tension. In this respect tentering,above defined, is equivalent to annealing. With respect to the presentinvention in its process aspect, annealing is involved with respect tothe yarns, mostly the fill yarns, wherein said yarns undergo a novelheating step prior to weaving. Further, it should be noted in connectionwith this term that in usual synthetic yarn manufacture and textileprocesses annealing times are rather short, e.g., less than one minuteand such annealing is carried out as part of a continuous process inmanufacture. The novel means of this invention involves times of manyminutes and usually hours. As such it is more analogous to conventionalmetal annealing, unheard of in textiles, and in this context might asaptly be referred to as heat soaking. Therefore, as will be describedmore fully, in its process aspects, this invention contemplates suchheat soaking or annealing steps, of longer times, and as will be seen,with the yarn immobile.

DENI ER The term used in the textile arts to define textile yarn sizesor fineness Denier as used herein is the weight in grams of 9000 metersof yarn. Thus a 500 denier yarn is a yarn such that 9000 meters of itweighs 500 grams.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 discloses, in cross sectionalong the front edge of a fill yarn, and across the warp yarns, aconstruction of a needle punched carpet showing the relative positionsof a scrim and the upper and lower fiber layers;

FIG. 2 is a top view of a needle punched fabric having portions of theseveral layers exposed to view;

FIG. 3 is a view of a corner of the scrim of the invention showing oneof the selvages thereof and the novel reinforcing wary yarns therefor;

FIG. 4 is a view taken on line 4-4 of FIG. 3;

FIG. 5 is a top view of an interior portion of the invention;

FIG. 6 is a view taken on line 66 of FIG. 5; and

FIG. 7 is a view taken on line 77 of FIG. 5.

DETAILED DESCRIPTION OF THE *INVENTION Referring to FIG. 1, across-section of a portion of a carpet, or fabric 10, prepared by aneedle punched process is illustrated, which comprises a scrim 15, abatt or web 11 and punched fibers 12 which are directed in and throughscrim, or backing 15. The section of the view is considered as beingtaken across the warp yarns 14 and along the front edge of one of thefill yarns 13. Warp and fill yarns 14 and 13, respectively form scrim 15which is a woven fabric. As seen in FIG. 1 the needle punching operationforces some of the fibers or batt 11, such as fibers -12 to be punchedthrough scrim 15 and thereafter to the underside 16 thereof. A latexcoating 16-a is applied to underside of fabric 10 of which underside 16is the bottom thereof providing an anchor for the punched in fibers 12.An additional backing of foam rubber 16-b or the like is adhesivelyfixed to the underside 1'6 and latex coat 16-a if such is desired.

Referring now to FIG. 2 a portion of fabric 10 is shown wherein isexposed the various layers which comprise the top of latex layer 16a,scrim 15 and its warp and fill yarns 14 and 13 respectively, and the topof batt 11 after fibers 12 have been punched through. Scrim 15 in theportion exposed is illustrative of a nominal, preferred number of warpyarns 14, as shown, being thirty in number (the warp yarns runningvertically in FIG. 2), and fill yarns 13, six in number. Thus apreferred scrim 15, which is herein referred to as a 30 x 6 scrim is inactuality one having, anywhere from 28 to 31 or 32 warp ends 14 and from4 to 7 fill ends or picks 13. Hence it should be realized, for bettercomprehension of the inventive concepts herein presented, that anexpression such as 30 x 6 when applied to the weave configuration ofscrim 15, is intended to convey that these are nominal yarn numbers inthe range above set forth.

FIG. 3 is illustrative of a corner-edge portion of scrim 15 in anotherembodiment, although the arrangement and type of woven yarns as well asthe relationship of ends per unit length of warp to fill is retained asin the preferred embodiment. Scrim 15, as illustrated in FIG. 3, is anexample of one woven on a shuttle-less machine such as the Sulzer loomabove referred to, and a selvage edge 17 automatically is formedthereby. In forming selvage 17, however, fill yarns 13 are cut, as at Ain FIG. 3, leaving ends 18 which are thereafter tucked in and throughwarp yarns 14 a short distance (see also FIG. 4). However, selvage 17thus obtained had some disadvantages when scrim 15 was used in a needlepunched carpet, chief among which was insufiicient yarn holding powerduring punching since the needles appeared to push some fill (andpossibly some warp) yarns through to the carpet face, or at least yarnwas visible thereat, hence an undesirable condition obtained. Means weretherefore much sought after to secure cut ends 18 and to prevent yarnpull-out from the selvage. Thus an adhesive applied along the selvageedge helped, as did heat application to fuse the selvage. However, thepreferred means discovered, and which is illustrated in FIG. 3, is toweave into scrim 15, at the edges, thereof, several (four are shown)monofilament warp yarns, as for example, round yarns 19, of sufficientdenier (and therefore stiffness) to insure that fill yarns 13 are wellcrimped thereat. It has been found that a round polypropylene yarn 19 ofabout 400 to about 700 denier, preferably one of about 550 to about 600denier (the ones shown in FIG. 3 are 565 denier) will cause amplecrimping of fill yarns 13. Crimping of fill yarns 13 at the edge resultsin a secure, reinforced selvage 17 and supplies more than ample holdingpower thereto so that little or no scrim 15 yarn is pushed up intocarpet 10 face yarn 12 thereby avoiding any unsightliness thereat. Itis, of course obvious that the desired crimping will be promoted byclosely spacing yarns 19 in selvage 17. Accordingly a new and novel, aswell as useful, additional embodiment of inventive scrim 15 is presentedto the textile and needle punching arts.

FIG. 4 illustrates the tucking in of cut ends 18 of fill yarns #13,being woven into scrim 15 through warp yarns 19 and 14 to form newselvage 17.

In the preparation of a needle punched fabric such as carpet 10, asmentioned above, many problems were encountered in using a woven scrimtherefor. A prior art scrim prepared from polypropylene ribbon-likeyarns woven on conventional looms with twelve ends per inch in the warpand eight ends per inch in the fill performed generally satisfactorily.However, the same weave configuration, woven on the new, more economicshuttleless (Sulzer) machines, inexplicably presented heretoforeunencountered problems. For example, as noted above, the scrim yarnssuch as yarns 13 being pushed through to the face of carpet resulting inan unsightly appearance, apparently caused by the needles holding someof the scrim yarns and forcing them up through the fibers of the battresulting in clogged needles, increased machine down time and otheroperating difficulties.

It was quite unexpected, of course, to find that the heretoforeapparently satisfactory weave configuration now performedunsatisfactorily when fabricated on the new, shuttle-less machines. Thisvexing problem remained unsolved, until the observation was made thatwhile the same number of fill ribbons, eight, were retained in the newmachine scrim, the coverage of these ribbons was increased ever soslightly because there was less twisting and folding thereof in weaving,in contrast to the older, shuttle machine weave. This increase incoverage by the fill yarns, though barely perceptible, was considered tobe, at least in part, at fault. Other factors which contributed to theproblem remained, including the fact that warp yam tension was somewhathigher with the new machines. Another contributing factor was theinsufiiciently secured fill end 13 in the selvage above mentioned.

Another problem, not related to the means for weaving was that ofexcessive width reduction occurring during the later stages of theneedle punching process, wherein the scrim, such as scrim 15, issubjected to heating and mechanical stresses which also tend to affect,adversely, the ability of the scrim to resist shrinking.

Width reduction occurs primarily because, in carpet manufacturing, theapplication of restraining forces to prevent such reduction, are not, asa practical matter, easily applied. Also, it is not usually feasible tocompensate for width reduction by increasing the scrim Width beforeprocessing because of the Width limitations of commercial weavingmachines. Nevertheless, width retention is of great importance to needlepunched carpet manufacturers, since, with zero or acceptably low scrimwidth reduction, wider carpets can be manufactured and trimming of thefiber batt eliminated. This results in significant labor savings andother cost reductions including a saving in material, particularly ifthe finished product is cut into square tiles such as the 9 inch by 9inch by 12 inch by 12' inch tiles now finding their way into the marketfor use in kitchens, bathrooms, patios etc.

It was found that width reduction particularly that due to the latexapplication step, i.e., heat shrinkage, in the carpet manufacturingprocess, was eliminated by annealing; however other factors are believedto be involved when total shrinkage, including shrinkage due tomechanical working, is to be eliminated, or at least minimized. A zeroshrink scrim 15, therefore, is provided by this invention being onewhich has zero shrin filling yarns, i.e., less than 0.5% shrink at 270R, which filling yarns were obtained by the novel step, as will beexplained, of heat soaking, or annealing fill yarns 13 preferably priorto weaving, although it should be understood that such annealing mayalso be accomplished after weaving yet without resorting to a tenteringprocess.

With respect to shrinkage due to mechanical working of the fabric asreferred to hereinbefore, and henceforth to be referred to as mechanicalshrink, it should be noted that this occurs because during weaving andpunching fabric 15 is stretched and tensioned, especially inshuttle-less loom weaving. Also with prior art weave configurations,i.e., one having 24 warp yarns of ribbons 0.100 inch wide and 0.002 inchthick, there is a greater tendency for the ribbon to foldover on itselfduring weaving, therefore reducing the warp Crowdednoss N0. appreciably.

Consider therefore, the following example by way of 8 comparison of theabove prior art scrim and the present invention and the relativetendencies of each warp yarn to foldover.

It has been observed that in a scrim weave of 12 ends per inch in thewarp woven from ribbon yarns 0.100 inch wide by 0.002 inch thick and aCrOwdedness N0. of 1.20, (see table above) the ribbon nearly always fitsitself into a confined lateral space by folding over 180 on itself to afiat condition (effectively reducing the Crowd-edness No. to less than1.00). By actual observation the warp ribbons in such a fabric vary inwidth according to the degree of folding: from 0.100 inch (no folding)to 0.030 inch.

On the other hand a sample of scrim 15 of this invention having 29 warpribbons 14 per inch each of 0.048 inch in Width and 0.002 inch inthickness, thus having the same thickness as the prior art yarns, andmanufactured in the same way and from the same polypropylene, has aCrowdedness N0. of 1.39 (see table above). However no appreciablefoldover was observed, instead ribbons 14 of scrim 15 accommodatethemselves in the limited lateral space by various means: bowing inspring-like fashion, as illustrated in FIG. 6, cocking at an angle tothe plane of the fabric (FIG. 4), and edge crimping and distorting atpoints of crossing past adjacent warp ribbons 14 (FIGS. 5 and 6).Elsewhere, while lateral space is ample, i.e., above and below fillribbons 13 warp yarns 14 are flat, in full, unfolded width, and usually,as shown in FIG. 7, even rise above (or fall below) fill yarns 13 asmall distance h (see FIG. 7). Thus What should be evident from this isthat scrim of this invention is relatively loosely woven, yet possessinggood body (low sleaziness) and having a high degree of springiness.These characteristics combine and render fabric 15 quite unique, in thatnot only is width reduction caused by fill yarn shrinkage due to heatapplication eliminated, but width reduction caused by mechanical shrinkis also eliminated. And, as discussed below, still further advantagesaccrue from use of the present invention and its novel weaveconfiguration and selection of yarns therefor.

An acceptable fabric, whether manufactured by the needle punched processor otherwise, must have good lay-fiat characteristics. In order toinsure good lay-flat in a carpet, the scrim or backing fabric must alsohave good lay-flat qualities, hence in using a woven scrim of plasticyarns, uneven tension in the warp direction i.e., a difference intension from yarn to yarn, sometimes causes puckering (the presence inthe fabric surface of waves and ripples, especially noticeable when thesurface is viewed obliquely) which results in non-flatness of the scrim.

It was unexpectedly found that scrim 15 of this invention had superiorflatness, and further, when used in a carpet gave a flat carpet. Onereason for this is that the invention of scrim 1*5 possesses a lowerrelatively uniform, warp tension due to its loosely woven quality (seeFIGS. 4 and 7) which relieves or eliminates the ill effects of tensiondifferences, giving a flat appearing fabric surface as one result. Inaddition the number of warp ends 14 being increased to a high 1)Crowdedness No. distributes any individual non-uniformities in a morebeneficial manner. It should also be noted that within the needle punchfabric industry, it has always been a working rule of thumb that toobtain good lay flat characteristics in a carpet one must have thin,smooth i.e., non-Woven, scrims. In contrast, scrim 15 of this inventionis on the order of twice the thickness of usual scrims and quite roughin surface texture for reasons which will become more apparent from whatfollows hereinafter.

Still another problem which arises in needle punched carpetmanufacturing is that of the batt of face fibers shifting after beingdeposited on the scrim and before the loaded scrim enters the needlebattery of the needling machine. Batt shifting such as this results innon-uniform carpet thickness and non-uniform coloration thereof.

The ill effects of this problem were eliminated by the advent of scrim15 of this invention since the surface thereof is sufficiently roughtextured to more than adequately prevent shifting and slipping of batt11. Scrim 15 is rough-textured because of, as clearly shown in FIGS. 4,5, and 7, its relatively low warp tension and the presence of cocked, orbowed warp yarns 14 due to crowd ing i.e., high Crowdedness N0., andhigh resistance to foldover of the ribbons, (See FIG. 6.)

-An additional means for prevention of batt shifting which can beapplied, and which is within the scope of the present invention is thesurface treatment of scrim 15 with a lubricant as disclosed in Kennedy,C. T. application Ser. No. 453,478 filed May 5, 1965, and now Pat. No.3,613,612. As described in that patent improved strength retention aftertufting of a woven backing used in tufted carpets can be achieved byapplying to the yarns prior to weaving, or to the backing prior totufting, from 0.2 to 12% by weight of a suitable lubricant. Suitablelubricants include mineral oil, polyethylene glycol esters such as thestearate, laurate and oleate, high molecular weight polyglycols andvarious low molecular weight waxes. Such treatment can be applied toscrim 15 in the same manner and for the same reasons, i.e., strengthretention after needling. However, a further benefit is realized in thatthe pesence of the lubricant on the yarns 13 and 14 or the surface ofscrim 15 tends to reduce electrostatic charge buildup which in turn mayrepel the batt rendering it more shiftable before punching. It is ofcourse not to be assumed that a non-lubricated scrim is inapplicable tothe invention herein, as it should be understood that scrim 15 in anunlubricated state is fully contemplated for the purposes of thisinvention.

Another problem, again related to the change from conventional toshuttle-less looms, was encountered in rolling a length of woven scrimfabric wherein a phenomenon known to the art as dog boning" occurred.Dog boning is, as the name implies, descriptive of a roll of scrimfabric having ends of significantly larger diameter than the middleportions and was found to occur because the selvages created by theSulzer loom are thicker than the middle part due to tucked-in cut fillends 18. Problems arise when the scrim fabric is removed from a rollsince in the rolled condition yarn tensions are higher at the selvageedges which causes the scrim inner portions to loosen resulting in wavesand ripples to give an unacceptable scrim fabric, one which will not layflat.

Dog boning has been eliminated by use of the scrim fabric 15 of thisinvention because, as illustrated in FIG. 4, the over-all averagethickness thereof is greater than prior art fabrics. The increasedthickness, due to such factors as looser weave, low warp yarn tension,and the fact that high coverage in the warp (high Crowdedness N0.results in a floating warp (see FIG. 4 and warp yarns 14 therein.) Itshould be realized that while FIG. 4 is not necessarily to scale it isquite representative of the true relationship of the warp to fill yarnpositions throughout scrim 15.

The above problems, and other hereinafter to be refered to, have beensubstantially overcome by the use of this invention, or, as earlierexplained, have been so dealt with that any deleterious effects havebeen mitigated to an extent which, for that reason alone, the inventionis believed to be a remarkable advance in the art of scrim fabrics forneedle punched carpets, as well as the art of carpet making itself.

In its process aspects inventive scrim 15 is prepared from polyolefinribbon yarns, preferably of isotactic polypropylene, which are orientedby stretching from 3 to 8 times, preferably about /2 times theiroriginal length. The denier of the warp yarns ranges from 250 to 700,preferably from 300 to 700. A particularly good working yarn denier is500. The preferred yarns have a cross-sectional width ranging from 0.024to about 0.140 and a thickness ranging from 0.001 to 0.003" and a mostpreferable ribbon is 0.048" x 0.002". Warp yarn shrinkage at 270 F. iswithin the range of from 0 to 10%, although 3% is most preferred. Ingeneral, yarns in the warp should be dimensionally selected in crosssection so as to be sufficiently stiff to insure a high resistance toribbon foldover thereby manifesting an ability to give a high degree ofspringiness to the scrim. Therefore, since stiffness is dependent uponthe ribbon width to thickness ratio, a warp ribbon 14 having a ratio offrom about 12 to 1 to about 35 to 1 should be selected. It will, ofcourse, be appreciated that the final choice will be made taking intoconsideration the economics thereof. Hence, it has been found that toobtain the maximum number of desirable characteristics in a given scrim15 consistent with low cost, use of the above preferred 0.048" x 0.002"(24 to 1 width to thickness ratio) ribbon for the warp yarns 14 resultsin an optimal selection.

Deniers of the fill yarns which can effectively be used range from 400to about 1700, preferably from 700 to about 1250, while a particulardenier of 1100 is most effectively accommodating. Isotacticpolypropylene material for the fill yarn ribbons is also most preferred,their cross sectional width ranging from 0.040 to 0.150 inch, and theirthickness from 0.001 to 0.003 inch, although the most preferredcross-sectional dimensions are, nominally 0.100 x 0.002 inch. Shrinkageof the fill yarns should be limited to from about zero to about 2.0% at270 F., although a limit of about 0.5% is preferred and readilyobtainable by means of the present invention. After orientation thefilling yarn is wound on a spool or tube package, and prior to weavingis heat soaked, or annealed by heating at a temperature ranging fromabout 270 F. to about 325 F, with the tube immobile in an oven forperiods ranging from at least one hour to a day or more, although aperiod of six to eight hours usually is preferred After heat soaking theyarn is set up on the loom and scrim 15 is prepared. Scrims having warpends 14 in almost any number can be made although a range of about 20 to45 ends per inch is most desirable. A most preferred number is nominallyabout 30 which, in practice, will range from 27 to about 32 ends perinch. Correspondingly, the fill yarns number from 4 to 10 per inch,although nominally 6 filling ends, or picks per inch encompassing arange of 5 to 7 is most preferred. Crowdedness Numbers preferably rangefrom about 1.10 to about 1.55, the most preferred being about 1.39. Thepreferred fabric, as noted above, is woven on a shuttle-less machine foreconomic reasons. The problem of securing the fill ribbon at eitherselvage edge is accomplished by use of several ends of 550 to 600denier, round monofilament polypropylene warp yarns 19 in selvage 17,closely spaced in order to crimp the ribbon fill yarns 13 to secure saidcut ends 18 thereof after ends 18 are tucked back into the edge of scrim15. These relatively stiffer polypropylene monofilaments not onlyadequately secure cut ends 18 but are so closely spaced, and the beadformed at the edge so narrow, that the diameter of large fabric rolls isno greater at either end than in the middle. Therefore dog boning iseliminated, although, as referred to above, the thickness of the fabricitself gives a unifom diameter when rolled, which in turn, is, in part,a result of crowding, .(high Crowdedness N0.) of warp ribbons 14,coupled with weaving thereof with little or no folding, due to thestiffness as determined by the prefered width to thickness ratio of 12to 1 or higher and low tension therein to give a relatively overallthick, rough-textured scrim fabric 15.

Scrim 15 and fabric 10 containing scrim 15 can be processed insubstantially any length, width or thickness depending upon theapparatus being employed. As a practical matter widths of twelve tofifteen feet are most commonly encountered in the trade. Wider scrimshowever, can be made and are supplied to the needle punch 1 1 fabricatorand are within the scope of the present invention.

Referring now to FIGS. 5 and 6 there is illustrated a portion of fabric15 inboard of the edges. FIG. 5 indicates the effect of crowding thewarp yarns, and is a presentation, substantially to scale, of a nominal30 x 60 scrim 15. The filling is somewhat open" since fill yarns 13 arespaced apart, and lies quite flat, i.e., substantially uncrimped,although an occasional one may have a slight twist as indicated byportion 13a in FIG. 7.

FIG. 6 is a representation of the manner in which warp yarns 14 crowdin, cock or bow when, in scrim 15, they pass over and under fill yarns13. Fill yarn 13 is also shown and it should be noted that it isuncrimped even though the warp, as shown, has a high (1.39) CrowdednessNumber. Reference to FIG. 4 even more clearly illustrates the lack ofcrimping in fill yarns 13 (except, of course at selvage 17 where specialmeans is provided to insure crimping). However, elsewhere throughoutfabric 15 crimping in the fill direction is almost nonexistent and ithas been found not only unnecessary, but in fact to be undesirable, incontrast to prior art scrims wherein the warp, when the number of yarnends were increased, it was for the purpose of insuring fill yarn crimp.In the prior art fill crimping is considered desirable, because inreducing width reduction caused by shrinkage of fill yarns, a crimpedfill yarn was understood to provide increased length, or slack, in thefilling yarns. This expediency has been found totally unnecessary by useof the inventive scrim 15 hereof, since fill yarns 13 are treated in anovel and inventive manner whereby, regardless of the heat producingstresses applied later on in manufacturing, fabric 15 is substantiallynon-shrinking.

As referred to earlier in this specifiction, an advantage of theinvention embodied in scrim 15 comprising a crowded warp and anuncrimped fill is the ability thereof to resist tendencies to sufferadversely from objectionable width reduction when subjected tomechanical working stresses, i.e., mechanical shrink, whereby a tendencyof the fabric to neck-down or draw in when placed under warp-wisetension occurs. Scrim 15, because of its high Crowdedness No. combinedwith the fact that it is relatively loosely woven and possessingspringiness will, when stretched warp-wise, tend to uncock, unbow orundistort its warp yarn 14, especially at the interweave sections shownin FIG. 6, thereby substantially preventing, or more precisely,successfully opposing any tendency of the overall fabric to suffer widthreduction due to neck down.

Accordingly what has also been developed, invented and described hereinis a novel woven fabric useful as a scrim in needle punched fabrics,which comprises warp yarns of synthetic plastic, loosely woven in afabric so as to be highly crowded therein with a substantially uncrimpedfill, said fill being substantially open.

The following examples are therefore presented to illustrate several ofthe various possible applications for the present invention.

EXAMPLE I A plain weave fabric was woven on a shuttle-less loom frompolyethylene glycol ester type lubricated polypropylene ribbon yarns.The yarns were oriented by stretching 5.5 times their original lengthand the woven fabric contained relatively stiff, 29 ends per inch of 500denier ribbon, 0.47" x 0.002 in cross section and a warp Crowdedness No.of 1.39. The fill contained 6 ends per inch of 1100 denier ribbon havinga cross section of 0.100 X 0.002", said filling yarn being earliersubjected to a heat soak at a temperature of 290 F. for 24 hours, whileimmobilized, to give a 0.0% 0.l%) shrinkage at 270 F. The selvages ofthe fabric were tucked back and contained 4 ends of 565 denier roundmonofilament yarns of polypropylene at each edge for securing the cutfill yarn ends. Overall fabric width was 152.9". This fabric was used asthe scrim in a typical needle punch operation.

The batt of face fibers exhibited no slippage so that carpet appearanceand thickness were uniform. Punching through of scrim yarn which wasvisible on the face of the carpet was minimal and acceptable. The fabricwidth reduction was very slight, to 152" after needling, latexing (aprocess wherein a liquid latex is applied to the bottom side of thecarpet) and drying on rolls heated to 285 F. The lay-fiat of the carpetwas good. The carpet grab strength was acceptable, being 124 lbs. in thefill direction and lbs. in the warp direction.

EXAMPLE II The scrim fabric of Example I was processed in a differentstyle carpet in a series between sections of a conventional scrim of 12x 8 ribbon-to-ribbon construction of 0.100" x 0.002 cross section (50 to1 width to thickness ratio) which had been heat set by tentering. Bothscrims were carried through identical processes to make a needle punchedcarpet. The Example I fabric suffered only a two inch width reductionwhereas the conventional scrim exceeded five inches in width reduction.Carpet from Example I scrim fabric also exhibited a superior flatnessand fewer polyproplyene ribbon yarns were observed to be visible in theface pile of the carpet. The latter advantage and improvement appears tobe the result of easier penetration by the needles into the scrim ofExample I resulting in less fracturing of the ribbons and therefore lesspushing through thereof into the carpet face. The easier penetrationresults from a more loosely woven, Example I scrim fabric, asdemonstrated by the low values for warp and fill pull out given in TableI here following, and also in the springlike quality inherent thereindue to the floating yarn characteristic illustrated in FIG. 4. Also, thefill being crimpless, permits easy side to side warp yarn movement andthe ribbons thereof collapse or move somewhat like venetian blind,slats, manifesting springiness.

TABLE I XAM. I Comparison of scrim fabrics for needle-punch carpetsPresent Prior art scrim invention Scrim fabric Warp Fill Warp FillMethod of weaving Shuttle-less Conventional shuttle loom loom fabricConstruction, nominal W x F 30 x 6 12 x 8 Construction, actual W x F 29x 6 12 x 8 Fabric wt., oz./sq. yd 2.6 2.8 Ribbon yarn cross-section: l

Warp, inches 0.048 x 0.002 0.100 x 0.002

Fill, inches--. 0.100 x 0.002 0.100 x 0.002 Fabric thickness, 0.0300.015 Fabric shrinkage, in

minutes:

At 270 F., percent 3. 1 0.0 2. 2 2. 3

At 290 F., percent 5. 6 1. 3 5.6 6.4 Fabric grab strength: 3

Lb. break 94 51 127 57 Percent bk. elong 26 24 24 15 Fabric yarnpull-out, gram 13 9 224 49 Fabric width, inches 153 152 Finished carpetfabric: 6

Width, inches .1 151 147 Carpet grab str.,1bs-- 124 9 126 Carpet wt.,oz./sq. yd 19.3 19.4

1 Dimenslonally and theoretically the 12 x 8 prior scrim appears to havea crowded warp and a 1.20 Crowdedness N0. However in practice due to thehigh percentage of warp yarn foldover and doubling up, the efiecttveCrowdedness No. Was observed to be at most about 1.0. Hence this scrimshould not be considered as having a crowded warp.

2 Scrim thickness measured as the separation of two steel plates, 4" x 4and $1 a thick. Scrim fabric is sandwiched between, with only thepressure of the weight of the top plate.

3 Standard textile test: 4 by 6 piece pulled at rate of 12" min. in longdirection; 3 between test jaws; width of jaws 1 inch.

4 Pull-out is a measure of sleaziness of the fabric. The value is theforce in grams to pull out one 3" long ribbon strand from the fabric.Test was run on both warp and fill.

Finished carpet; after scrim is needle-punched on both sides and latexapplied to one side, with exposure to 285 F. heat for curing the latex.

EXAMPLE III A scrim fabric differing from the scrim of Example I in thatthere were 45 ends per inch in the warp and 9 fill ribbon yarn ends perinch was made with ribbons 0.034" x 0.0015" warp (width to thicknessratio about 22). The warp ribbon displayed no foldover on observationafter weaving in the confinement of the fabric weave.

EXAMPLE IV A series of scrim fabrics similar to Example I scrim wereprepared as follows: each scrim fabric had nominally the same number ofwarp ends per inch (30), however one sample had 6 fill ends per inch,the second sample had fill ends and the third sample had 4 fill ends. Asin Example I, the six fill ends per inch scrim performed well, the fivefill ends per inch scrim fabric also performed satisfactory throughneedle punching. The four fill end per inch fabric was considered ofborder line quality mainly because of its sleaziness which gave somedifficulty in handling the bare scrim fabric, otherwise it appeared toperform well.

EXAMPLE V To prepare low or zero shrink filling yarn, the followingsteps were performed. Several filling yarn tube packages of 1100 denierpolypropylene ribbon were exposed i.e., heat soaked, or annealed byheating, to 290 F. air temperature for 24 hours. Each tube packagecontained eight pounds of filling yarn on a 3" diameter core wound to an8 /2" outside diameter and 6 in length. The fill yarn thus treated wastested and found to have 0.25% shrinkage of 270 F. after minutes in anair circulating oven. This yarn was thereafter used to make a scrimfabric of 0.0% 0.1%) shrinkage in the fill direction.

EXAMPLE VI A scrim fabric having a weave configuration of 24 warp endsper inch and 6 filling picks was prepared on a shuttle-less loom fromwarp ribbons nominally 0.050" x 0.002" in cross section (25 to 1 widthto thickness ratio) and 0.100" x 0.002" in cross section fill ribbons.The warp Crowdedness N0. was 1.20. The fill ribbons were run over a hotroll prior to being wound on a tube package prior to weaving, and thenthe fill yarn containing tube package was heated in a horizontal flowforced air oven with the tube positioned therein on its long, horizontalaxis for a period of from 4 to 6 hours at an air temperature of 290 F.The fabric was similar in appearance with respect to yarn foldover andspringiness to the fabric of Example I and when used in a needle punchedcarpet resulted in a carpet of similar appearance. The fabric in thisexample was unlubricated and had a selvage prepared by heat sealing theedges thereof.

The invention herein above described and alluded to is, of course,understood not to be limited solely to the embodiments shown, since manymodifications can be made by skilled artisans without departing from itsspirit and scope. For example the (nominally) x 6 fabric, is a zeroshrink, Sulzer or shuttle-less loom fabrc with zero or a negligibleamount of crimp in the fill yarns. It is believed that this feature asnoted hereinabove, is significant and contributes substantially to thewide spread acceptance of his inventive scrim fabric by the needlepunched carpet industry, at least as of the present time based onexperimental use thereof by the industry. It is known for example thatnon-crimp in the fill yarns would appear to run contrary to the widelyheld theory that any increase in number of warp ends would decreasewidth reduction in the fabric. This theory states that more warp endsper inch, i.e., greater crowding (increased Crowdea'ness N0.) means morecrimp in the fill, thus, greater length of the fill yarns in a givenwidth of fabric. However, as noted elsewhere herein, with the particularfabric of this invention, increasing the number of warp yarns to therebycrowd the warp with extra yarns, did not increase crimp in the fillyarns. Further, yarn tenacity is not decreased in the annealingtreatment. In fact some tests indicate that there may even be a slightincrease in tenacity. Yarn strength is also an important property inimparting strength to the final carpet and is one of the chief functionsof the scrim itself in needle punched carpeting. Therefore, what issought to be protected by Letters Patent of the United States should notbe limited except as indicated by the subtending claims.

What is claimed is:

1. A needle-punched fabric comprising a scrim woven of polyolefin warpand fill yarns, said warp yarns being fiat ribbons of substantiallyrectangular cross section and having a Crowdedness Number of at least1.10, said fill yarns being flat ribbons of substantially rectangularcross section and having a Crowdedness Number of less than 1.0, and saidfill yarns being substantially uncrimped in said scrim.

2. The fabric of claim 1 wherein the polyolefin is polypropylene.

3. The fabric of claim 1 wherein the filling yarns have been annealedprior to weaving in said scrim.

4. The fabric of claim 1 wherein the warp yarns have a denier in therange of from 200 to about 700.

5. The fabric of claim 1 wherein the filling yarns have a denier in therange of from 400 to about 1700.

6. The fabric of claim 3 wherein the filling yarns have been annealed byheating said yarns to a temperature of from 270 F. to about 325 F.

7. The fabric of claim 3 wherein the filling yarns have been annealedfor at least one hour.

8. The fabric of claim 1 wherein the Warp yarns have a clross sectionalwidth to thickness ratio of at least 12 to 9. The fabric of claim 8wherein the ratio is in the range of from 12 to 1 to about 35 to 1.

10. The fabric of claim 3 wherein the fill yarns have been annealed toless than 3.0% shrinkage at 270 F.

11. The fabric of claim 3 wherein the fill yarns of said scrim have beenannealed while wound on a tube package and immobile.

12. The fabric of claim 3 wherein the fill yarns have been run over ahot roll and thereafter wound on a tube package prior to weaving intosaid scrim.

. 13. The fabric of claim 1 wherein the ratio of ends per inch in thewarp to that of the fill is at least 3 to 1.

14. The fabric of claim 1 wherein the ratio of ends per inch in the warpto that in the fill is in the range of from 3 to 1 to about 10 to 1.

15. The fabric of claim 1 wherein said scrim includes selvagescomprising; at least one warp-wise monofilament yarn having asubstantially round cross section and closely spaced from said warp.

References Cited UNITED STATES PATENTS 1,922,739 8/1933 Lees 161-712,951,277 9/1960 Youngs 161-91 X 3,058,194 10/ 1962 Havner 161713,439,865 4/1969 Port et a1. 16l--71 X 3,443,541 5/1969 Chopra 161-653,542,632 11/ 1970 Eickhoff 2872.2 X

FOREIGN PATENTS 1,510,153 12/1967 France 139-422 R ROBERT F. BURNETT,Primary Examiner R. O. LINKER, 1a., Assistant Examiner US Cl. X.R.

